man > journald@.conf(5)

JOURNALD.CONF(5)                            journald.conf                           JOURNALD.CONF(5)



NAME
       journald.conf, journald.conf.d, journald@.conf - Journal service configuration files

SYNOPSIS
       /etc/systemd/journald.conf

       /etc/systemd/journald.conf.d/*.conf

       /run/systemd/journald.conf.d/*.conf

       /usr/lib/systemd/journald.conf.d/*.conf

       /etc/systemd/journald@NAMESPACE.conf

       /etc/systemd/journald@NAMESPACE.conf.d/*.conf

       /run/systemd/journald@NAMESPACE.conf.d/*.conf

       /usr/lib/systemd/journald@NAMESPACE.conf.d/*.conf

DESCRIPTION
       These files configure various parameters of the systemd journal service, systemd-
       journald.service(8). See systemd.syntax(7) for a general description of the syntax.

       The systemd-journald instance managing the default namespace is configured by
       /etc/systemd/journald.conf and associated drop-ins. Instances managing other namespaces read
       /etc/systemd/journald@NAMESPACE.conf and associated drop-ins with the namespace identifier
       filled in. This allows each namespace to carry a distinct configuration. See systemd-
       journald.service(8) for details about journal namespaces.

CONFIGURATION DIRECTORIES AND PRECEDENCE
       The default configuration is set during compilation, so configuration is only needed when it
       is necessary to deviate from those defaults. Initially, the main configuration file in
       /etc/systemd/ contains commented out entries showing the defaults as a guide to the
       administrator. Local overrides can be created by editing this file or by creating drop-ins,
       as described below. Using drop-ins for local configuration is recommended over modifications
       to the main configuration file.

       In addition to the "main" configuration file, drop-in configuration snippets are read from
       /usr/lib/systemd/*.conf.d/, /usr/local/lib/systemd/*.conf.d/, and /etc/systemd/*.conf.d/.
       Those drop-ins have higher precedence and override the main configuration file. Files in the
       *.conf.d/ configuration subdirectories are sorted by their filename in lexicographic order,
       regardless of in which of the subdirectories they reside. When multiple files specify the
       same option, for options which accept just a single value, the entry in the file sorted last
       takes precedence, and for options which accept a list of values, entries are collected as
       they occur in the sorted files.

       When packages need to customize the configuration, they can install drop-ins under /usr/.
       Files in /etc/ are reserved for the local administrator, who may use this logic to override
       the configuration files installed by vendor packages. Drop-ins have to be used to override
       package drop-ins, since the main configuration file has lower precedence. It is recommended
       to prefix all filenames in those subdirectories with a two-digit number and a dash, to
       simplify the ordering of the files.

       To disable a configuration file supplied by the vendor, the recommended way is to place a
       symlink to /dev/null in the configuration directory in /etc/, with the same filename as the
       vendor configuration file.

OPTIONS
       All options are configured in the [Journal] section:

       Storage=
           Controls where to store journal data. One of "volatile", "persistent", "auto" and "none".
           If "volatile", journal log data will be stored only in memory, i.e. below the
           /run/log/journal hierarchy (which is created if needed). If "persistent", data will be
           stored preferably on disk, i.e. below the /var/log/journal hierarchy (which is created if
           needed), with a fallback to /run/log/journal (which is created if needed), during early
           boot and if the disk is not writable.  "auto" behaves like "persistent" if the
           /var/log/journal directory exists, and "volatile" otherwise (the existence of the
           directory controls the storage mode).  "none" turns off all storage, all log data
           received will be dropped (but forwarding to other targets, such as the console, the
           kernel log buffer, or a syslog socket will still work). Defaults to "auto" in the default
           journal namespace, and "persistent" in all others.

           Note that journald will initially use volatile storage, until a call to journalctl
           --flush (or sending SIGUSR1 to journald) will cause it to switch to persistent logging
           (under the conditions mentioned above). This is done automatically on boot via
           "systemd-journal-flush.service".

           Note that when this option is changed to "volatile", existing persistent data is not
           removed. In the other direction, journalctl(1) with the --flush option may be used to
           move volatile data to persistent storage.

       Compress=
           Can take a boolean value. If enabled (the default), data objects that shall be stored in
           the journal and are larger than the default threshold of 512 bytes are compressed before
           they are written to the file system. It can also be set to a number of bytes to specify
           the compression threshold directly. Suffixes like K, M, and G can be used to specify
           larger units.

       Seal=
           Takes a boolean value. If enabled (the default), and a sealing key is available (as
           created by journalctl(1)'s --setup-keys command), Forward Secure Sealing (FSS) for all
           persistent journal files is enabled. FSS is based on Seekable Sequential Key
           Generators[1] by G. A. Marson and B. Poettering (doi:10.1007/978-3-642-40203-6_7) and may
           be used to protect journal files from unnoticed alteration.

       SplitMode=
           Controls whether to split up journal files per user, either "uid" or "none". Split
           journal files are primarily useful for access control: on UNIX/Linux access control is
           managed per file, and the journal daemon will assign users read access to their journal
           files. If "uid", all regular users (with UID outside the range of system users, dynamic
           service users, and the nobody user) will each get their own journal files, and system
           users will log to the system journal. See Users, Groups, UIDs and GIDs on systemd
           systems[2] for more details about UID ranges. If "none", journal files are not split up
           by user and all messages are instead stored in the single system journal. In this mode
           unprivileged users generally do not have access to their own log data. Note that
           splitting up journal files by user is only available for journals stored persistently. If
           journals are stored on volatile storage (see Storage= above), only a single journal file
           is used. Defaults to "uid".

       RateLimitIntervalSec=, RateLimitBurst=
           Configures the rate limiting that is applied to all messages generated on the system. If,
           in the time interval defined by RateLimitIntervalSec=, more messages than specified in
           RateLimitBurst= are logged by a service, all further messages within the interval are
           dropped until the interval is over. A message about the number of dropped messages is
           generated. This rate limiting is applied per-service, so that two services which log do
           not interfere with each other's limits. Defaults to 10000 messages in 30s. The time
           specification for RateLimitIntervalSec= may be specified in the following units: "s",
           "min", "h", "ms", "us". To turn off any kind of rate limiting, set either value to 0.

           Note that the effective rate limit is multiplied by a factor derived from the available
           free disk space for the journal. Currently, this factor is calculated using the base 2
           logarithm.

           Table 1. Example RateLimitBurst= rate modifications by the available disk space
           ┌─────────────────────┬──────────────────┐
           │Available Disk Space │ Burst Multiplier │
           ├─────────────────────┼──────────────────┤
           │<= 1MB               │ 1                │
           ├─────────────────────┼──────────────────┤
           │<= 16MB              │ 2                │
           ├─────────────────────┼──────────────────┤
           │<= 256MB             │ 3                │
           ├─────────────────────┼──────────────────┤
           │<= 4GB               │ 4                │
           ├─────────────────────┼──────────────────┤
           │<= 64GB              │ 5                │
           ├─────────────────────┼──────────────────┤
           │<= 1TB               │ 6                │
           └─────────────────────┴──────────────────┘
           If a service provides rate limits for itself through LogRateLimitIntervalSec= and/or
           LogRateLimitBurst= in systemd.exec(5), those values will override the settings specified
           here.

       SystemMaxUse=, SystemKeepFree=, SystemMaxFileSize=, SystemMaxFiles=, RuntimeMaxUse=,
       RuntimeKeepFree=, RuntimeMaxFileSize=, RuntimeMaxFiles=
           Enforce size limits on the journal files stored. The options prefixed with "System" apply
           to the journal files when stored on a persistent file system, more specifically
           /var/log/journal. The options prefixed with "Runtime" apply to the journal files when
           stored on a volatile in-memory file system, more specifically /run/log/journal. The
           former is used only when /var/ is mounted, writable, and the directory /var/log/journal
           exists. Otherwise, only the latter applies. Note that this means that during early boot
           and if the administrator disabled persistent logging, only the latter options apply,
           while the former apply if persistent logging is enabled and the system is fully booted
           up.  journalctl and systemd-journald ignore all files with names not ending with
           ".journal" or ".journal~", so only such files, located in the appropriate directories,
           are taken into account when calculating current disk usage.

           SystemMaxUse= and RuntimeMaxUse= control how much disk space the journal may use up at
           most.  SystemKeepFree= and RuntimeKeepFree= control how much disk space systemd-journald
           shall leave free for other uses.  systemd-journald will respect both limits and use the
           smaller of the two values.

           The first pair defaults to 10% and the second to 15% of the size of the respective file
           system, but each value is capped to 4G. If the file system is nearly full and either
           SystemKeepFree= or RuntimeKeepFree= are violated when systemd-journald is started, the
           limit will be raised to the percentage that is actually free. This means that if there
           was enough free space before and journal files were created, and subsequently something
           else causes the file system to fill up, journald will stop using more space, but it will
           not be removing existing files to reduce the footprint again, either. Also note that only
           archived files are deleted to reduce the space occupied by journal files. This means
           that, in effect, there might still be more space used than SystemMaxUse= or
           RuntimeMaxUse= limit after a vacuuming operation is complete.

           SystemMaxFileSize= and RuntimeMaxFileSize= control how large individual journal files may
           grow at most. This influences the granularity in which disk space is made available
           through rotation, i.e. deletion of historic data. Defaults to one eighth of the values
           configured with SystemMaxUse= and RuntimeMaxUse=, so that usually seven rotated journal
           files are kept as history.

           Specify values in bytes or use K, M, G, T, P, E as units for the specified sizes (equal
           to 1024, 1024², ... bytes). Note that size limits are enforced synchronously when journal
           files are extended, and no explicit rotation step triggered by time is needed.

           SystemMaxFiles= and RuntimeMaxFiles= control how many individual journal files to keep at
           most. Note that only archived files are deleted to reduce the number of files until this
           limit is reached; active files will stay around. This means that, in effect, there might
           still be more journal files around in total than this limit after a vacuuming operation
           is complete. This setting defaults to 100.

       MaxFileSec=
           The maximum time to store entries in a single journal file before rotating to the next
           one. Normally, time-based rotation should not be required as size-based rotation with
           options such as SystemMaxFileSize= should be sufficient to ensure that journal files do
           not grow without bounds. However, to ensure that not too much data is lost at once when
           old journal files are deleted, it might make sense to change this value from the default
           of one month. Set to 0 to turn off this feature. This setting takes time values which may
           be suffixed with the units "year", "month", "week", "day", "h" or "m" to override the
           default time unit of seconds.

       MaxRetentionSec=
           The maximum time to store journal entries. This controls whether journal files containing
           entries older than the specified time span are deleted. Normally, time-based deletion of
           old journal files should not be required as size-based deletion with options such as
           SystemMaxUse= should be sufficient to ensure that journal files do not grow without
           bounds. However, to enforce data retention policies, it might make sense to change this
           value from the default of 0 (which turns off this feature). This setting also takes time
           values which may be suffixed with the units "year", "month", "week", "day", "h" or " m"
           to override the default time unit of seconds.

       SyncIntervalSec=
           The timeout before synchronizing journal files to disk. After syncing, journal files are
           placed in the OFFLINE state. Note that syncing is unconditionally done immediately after
           a log message of priority CRIT, ALERT or EMERG has been logged. This setting hence
           applies only to messages of the levels ERR, WARNING, NOTICE, INFO, DEBUG. The default
           timeout is 5 minutes.

       ForwardToSyslog=, ForwardToKMsg=, ForwardToConsole=, ForwardToWall=
           Control whether log messages received by the journal daemon shall be forwarded to a
           traditional syslog daemon, to the kernel log buffer (kmsg), to the system console, or
           sent as wall messages to all logged-in users. These options take boolean arguments. If
           forwarding to syslog is enabled but nothing reads messages from the socket, forwarding to
           syslog has no effect. By default, only forwarding to syslog and wall is enabled. These
           settings may be overridden at boot time with the kernel command line options
           "systemd.journald.forward_to_syslog", "systemd.journald.forward_to_kmsg",
           "systemd.journald.forward_to_console", and "systemd.journald.forward_to_wall". If the
           option name is specified without "=" and the following argument, true is assumed.
           Otherwise, the argument is parsed as a boolean.

           When forwarding to the console, the TTY to log to can be changed with TTYPath=, described
           below.

           When forwarding to the kernel log buffer (kmsg), make sure to select a suitably large
           size for the log buffer, for example by adding "log_buf_len=8M" to the kernel command
           line.  systemd will automatically disable kernel's rate-limiting applied to userspace
           processes (equivalent to setting "printk.devkmsg=on").

       MaxLevelStore=, MaxLevelSyslog=, MaxLevelKMsg=, MaxLevelConsole=, MaxLevelWall=
           Controls the maximum log level of messages that are stored in the journal, forwarded to
           syslog, kmsg, the console or wall (if that is enabled, see above). As argument, takes one
           of "emerg", "alert", "crit", "err", "warning", "notice", "info", "debug", or integer
           values in the range of 0–7 (corresponding to the same levels). Messages equal or below
           the log level specified are stored/forwarded, messages above are dropped. Defaults to
           "debug" for MaxLevelStore= and MaxLevelSyslog=, to ensure that the all messages are
           stored in the journal and forwarded to syslog. Defaults to "notice" for MaxLevelKMsg=,
           "info" for MaxLevelConsole=, and "emerg" for MaxLevelWall=. These settings may be
           overridden at boot time with the kernel command line options
           "systemd.journald.max_level_store=", "systemd.journald.max_level_syslog=",
           "systemd.journald.max_level_kmsg=", "systemd.journald.max_level_console=",
           "systemd.journald.max_level_wall=".

       ReadKMsg=
           Takes a boolean value. If enabled systemd-journal processes /dev/kmsg messages generated
           by the kernel. In the default journal namespace this option is enabled by default, it is
           disabled in all others.

       Audit=
           Takes a boolean value. If enabled systemd-journal will turn on kernel auditing on
           start-up. If disabled it will turn it off. If unset it will neither enable nor disable
           it, leaving the previous state unchanged. Note that this option does not control whether
           systemd-journald collects generated audit records, it just controls whether it tells the
           kernel to generate them. This means if another tool turns on auditing even if
           systemd-journald left it off, it will still collect the generated messages. Defaults to
           off.

       TTYPath=
           Change the console TTY to use if ForwardToConsole=yes is used. Defaults to /dev/console.

       LineMax=
           The maximum line length to permit when converting stream logs into record logs. When a
           systemd unit's standard output/error are connected to the journal via a stream socket,
           the data read is split into individual log records at newline ("\n", ASCII 10) and NUL
           characters. If no such delimiter is read for the specified number of bytes a hard log
           record boundary is artificially inserted, breaking up overly long lines into multiple log
           records. Selecting overly large values increases the possible memory usage of the Journal
           daemon for each stream client, as in the worst case the journal daemon needs to buffer
           the specified number of bytes in memory before it can flush a new log record to disk.
           Also note that permitting overly large line maximum line lengths affects compatibility
           with traditional log protocols as log records might not fit anymore into a single AF_UNIX
           or AF_INET datagram. Takes a size in bytes. If the value is suffixed with K, M, G or T,
           the specified size is parsed as Kilobytes, Megabytes, Gigabytes, or Terabytes (with the
           base 1024), respectively. Defaults to 48K, which is relatively large but still small
           enough so that log records likely fit into network datagrams along with extra room for
           metadata. Note that values below 79 are not accepted and will be bumped to 79.

FORWARDING TO TRADITIONAL SYSLOG DAEMONS
       Journal events can be transferred to a different logging daemon in two different ways. With
       the first method, messages are immediately forwarded to a socket
       (/run/systemd/journal/syslog), where the traditional syslog daemon can read them. This method
       is controlled by the ForwardToSyslog= option. With a second method, a syslog daemon behaves
       like a normal journal client, and reads messages from the journal files, similarly to
       journalctl(1). With this, messages do not have to be read immediately, which allows a logging
       daemon which is only started late in boot to access all messages since the start of the
       system. In addition, full structured meta-data is available to it. This method of course is
       available only if the messages are stored in a journal file at all. So it will not work if
       Storage=none is set. It should be noted that usually the second method is used by syslog
       daemons, so the Storage= option, and not the ForwardToSyslog= option, is relevant for them.

SEE ALSO
       systemd(1), systemd-journald.service(8), journalctl(1), systemd.journal-fields(7), systemd-
       system.conf(5)

NOTES
        1. Seekable Sequential Key Generators
           https://eprint.iacr.org/2013/397

        2. Users, Groups, UIDs and GIDs on systemd systems
           https://systemd.io/UIDS-GIDS



systemd 249                                                                         JOURNALD.CONF(5)